Daily probiotic may help ease depression and anxiety

Researchers in India found that older patients with moderate depression who took a probiotic containing Lactobacillus helveticus and Bifidobacterium longum experienced greater overall improvements in mood and anxiety symptoms than those who received a placebo.

The study involved 58 adults aged 60 and older diagnosed with moderate unipolar depression. Participants were randomly assigned to receive either a probiotic supplement or a placebo for 12 weeks while continuing standard antidepressant care. Researchers then monitored them for an additional 12 weeks.

Both groups showed substantial improvement over the six-month study period. However, participants in the probiotic group recorded lower overall scores for depression and anxiety, suggesting an added benefit from the supplement.

The researchers also observed biological changes that may help explain the effect. Patients taking probiotics showed increased levels of brain-derived neurotrophic factor (BDNF), a protein linked to brain health, mood regulation, and neural resilience. Stool samples also confirmed a significant increase in the abundance of the probiotic strains provided during the trial.

Despite the improvements in mood and anxiety, probiotics did not provide additional gains in quality of life compared with standard treatment alone. Quality-of-life measures improved in both groups at similar rates.

The supplement was generally well tolerated. Some participants in the probiotic group reported mild digestive symptoms such as bloating, abdominal fullness, and constipation during the first weeks of treatment, but no serious psychiatric side effects were recorded.

The authors said the findings support the growing idea that the gut microbiome can influence mental health through the so-called gut-brain axis, a communication network linking the digestive system and the brain.

However, they cautioned that the results should be interpreted carefully. The trial was relatively small, involved only 58 participants instead of the planned 80, and more than half of the participants dropped out before the study ended. Differences in antidepressant medications prescribed during the trial may also have influenced the results.

Earlier, Qazinform News Agency reported that a simple blood test could reveal hidden depression.